Abstract Early intervention to identify and treat chronic disease and modify behavioral risk factors among women of reproductive age has the potential to significantly reduce their morbidity and mortality and improve their pregnancy outcomes. Lack of health insurance has been a major barrier to early intervention and preventive care among low-income women of reproductive age. However, the 2014 expansion of Medicaid under the Patient Protection and Affordable Care Act (ACA) will make millions of low-income women newly eligible for Medicaid and preventive health services. An integrated data system is essential to evaluate the impact of this expansion on the health of women of reproductive age and their infants. Research using this data system will inform future program planning and identify best practices and areas of greatest need. We propose to create an integrated data system that links Oregon Medicaid data with birth and death certificates and hospital discharge data. Further, we will include data on the quality of Medicaid services that are not available to other states. The proposed study is a collaborative effort between Oregon State University and the Oregon Health Authority. Oregon is an ideal state in which to conduct the proposed study because of its ongoing commitment to Medicaid health care delivery reform and the commitment of state leaders to collaborate across divisions and programs to ensure this project's success. The project also has the support of key state stakeholders in maternal and child health and women's health. The specific aims of the proposal are to1) develop a research agenda, in collaboration with key stakeholders, to evaluate the expansion of Medicaid on the health of Medicaid-eligible women of reproductive age, mothers, and infants in Oregon; 2) link Oregon Medicaid data for female enrollees ages 15-44 and their infants to statewide datasets, including (but not limited to) live birth, fetal death, infant death, and hospital discharge data, beginning with 2008 and continuing until 2016, as data become available; and 3) conduct planned analyses and disseminate findings. The research agenda will include key research questions that assess the effect of Medicaid expansion on Medicaid enrollment and access to care for low-income women; utilization of services by women and infants enrolled in Medicaid; general health behaviors, risks, and outcomes for these women; and pregnancy complications and poor birth outcomes. We will also measure disparities that remain after Medicaid expansion, to inform strategies to mitigate those disparities on an ongoing basis. We will use results of these analyses to construct simulations that extend this study's findings into implications and lessons for policy makers and stakeholders in other states that are expanding Medicaid. Results of these analyses and simulations will provide valuable information to support health reform efforts, both in Oregon and across the U.S, to reduce the public health burden and improve population health among women of reproductive age, including pregnancy and infant health outcomes.